How to programmatically alter an existing stl (stereolitography) file on a linux server?

Question

I would like to modify some aspects of an stl file, created with solidworks, on a linux server. Is there a tried and tested way for such a task? I am looking into 3d libraries or meshlabserver at the moment.

Answer 1

You can use meshlabserver like this

meshlabserver -i sourcefilepath -o resaultfilepath -s process.mlx

You need to write the process.mlx file to define the operation on you model

For example half the scale on z axis with below process.mlx

<!DOCTYPE FilterScript>
<FilterScript>
 <filter name="Transform: Scale, Normalize">
  <Param value="1" type="RichFloat" description="X Axis" name="axisX" tooltip="Scaling"/>
  <Param value="1" type="RichFloat" description="Y Axis" name="axisY" tooltip="Scaling"/>
  <Param value="0.5" type="RichFloat" description="Z Axis" name="axisZ" tooltip="Scaling"/>
  <Param value="false" type="RichBool" description="Uniform Scaling" name="uniformFlag" tooltip="If selected an uniform scaling (the same for all the three axis) is applied (the X axis value is used)"/>
  <Param value="0" enum_val0="origin" enum_val1="barycenter" enum_val2="custom point" type="RichEnum" description="Center of scaling:" name="scaleCenter" enum_cardinality="3" tooltip="Choose a method"/>
  <Param type="RichPoint3f" x="0" y="0" description="Custom center" z="0" name="customCenter" tooltip="This scaling center is used only if the 'custom point' option is chosen."/>
  <Param value="false" type="RichBool" description="Scale to Unit bbox" name="unitFlag" tooltip="If selected, the object is scaled to a box whose sides are at most 1 unit lenght"/>
  <Param value="true" type="RichBool" description="Freeze Matrix" name="Freeze" tooltip="The transformation is explicitly applied, and the vertex coordinates are actually changed"/>
  <Param value="false" type="RichBool" description="Apply to all visible Layers" name="allLayers" tooltip="If selected the filter will be applied to all visible mesh layers"/>
 </filter>
</FilterScript>

If you are not familar with the mashlab mlx file, you can generate it with the mashlab like this,

Filters > Normals, Curvatures and Orientation > Transform: Scale, Normalize

Then set the scale in the window, you can uncheck the Uniform Scaling checkbox to scale each axis separately

Then click the apply button.

Finally, Filters > Show current filter script, you can see the current scripts here, select the Tansform: Scale, Normalize and click the Save Script as the process.mlx